Fig. 3.

The assembly and evolutionary roles of generalist and specialist groups. (a) Assembly of different groups based on the null-model-based framework. The inner circle represents the contribution of stochastic and deterministic processes to community assembly. The outer circle represents the percentage of detailed ecological processes statistically assigned to stochastic or deterministic processes. The original dataset represents the entire community, the specialist truncated represents the dataset after removing specialists, and the generalist truncated represents the dataset after removing generalists. (b) The nearest taxon index (NTI) to assess the phylogenetic structure of different groups. A higher NTI indicates that the community exhibits more phylogenetic clustering and a NTI close to 0 indicates the community is phylogenetically random. (c) Estimation of the neutral processes based on the Sloan neutral model. The parameters R² and m represents the goodness of fitting and migration rate, respectively. The species that occur more and less frequently than predicted are shown in yellow and green, respectively. Dashed lines represent 95% confidence intervals and the species falling within the confidence intervals are considered neutrally distributed. (d) The modified stochasticity ratio (MST) of different groups based on Bray-Curtis and Jaccard distance. The higher MST indicated the community assembly was more stochastic. (e) Evolutionary characteristics of the generalists and specialists based on the binary-state speciation and extinction (BiSSE) model. The distribution of speciation rate, extinction rate and transition rate are shown, and their average values among the specialist and generalist groups were provided.